# Monthly Archives: July 2011

## Le Monde puzzle [#29]

July 28, 2011
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$Le Monde puzzle [#29]$

This week, the puzzle from the weekend edition of Le Monde was easy to state: in the sequence (8+17n), is there a 6th power? a 7th? an 8th? If so, give the first occurrence. So I first wrote an R code for a function testing whether an integer is any power: (The function returns the

## Pattern Recognition: forward Boxplot Trajectories using R

July 28, 2011
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Although the following discussion can apply to the Quantitative Candlestick Pattern Recognition series, it is addressing the same issue as any basic conditional type system -- how and when to exit.  The following is one way to visualize and think ...

## Program for useR! 2011 available

July 28, 2011
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The final program for the worldwide user conference, useR! 2011, is now available as a downloadable booklet (PDF, 7Mb). Revolution Analytics is very proud to sponsor this annual gathering of R users from around the world, and the program includes an outstanding lineup of speakers from the R Core Group, package developers, users in industry and academia, and the...

July 28, 2011
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It always strikes me as curious that some posts get a lot of love on Twitter, while others get many more shares on Facebook: What accounts for this difference? Some of it is surely site-dependent: maybe one blogger has a Facebook page but not a Twitter account, while another has these roles reversed. But even

## Getting rid of white space at the beginning and end of a string

July 28, 2011
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There are situations where we are working with character strings extracted from various sources and it can be annoying when there is white space at the beginning and/or end of the strings. This whitespace can cause problems when attemping to sort, subset or various other common operations. The stringr package has a handy function str_trim

## I can’t resist a word cloud: now using R!

July 28, 2011
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The wordcloud package is word clouds for R with a difference: they look great. Of course, having just analysed online coverage of the ISMB conference, I had to run all 6 906 comments from the 2008-2011 meetings through some code. If you followed along via the Sweave code, I went as far as generating the

## More S&P 500 correlation

July 28, 2011
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Here are some additions to the previous post on S&P 500 correlation. Correlation distribution Before we only looked at mean correlations.  However, it is possible to see more of the distribution than just the mean.  Figures 1 and 2 show several quantiles: 10%, 25%, 50%, 75%, 90%. Figure 1: Quantiles of 50-day rolling correlation of … Continue reading...

## Displaying Missouri sex offender/child day care facility proximity map using batchgeo.com

July 28, 2011
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Computer Assisted Reporting This is the last of four articles about analyzing distances between sex offenders and child daycare centers in Missouri as part of a joint project with KSHB NBC Action News in Kansas City. The previous two articles gave deta...

## Marketing optimization using the nonlinear minimization function nlm

July 28, 2011
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Guest post by Bob Agnew ([email protected]) —————- Introduction Marketing optimization consists of assigning offers to prospects in order to maximize total expected profit subject to a few general linear constraints and the requirement that a prospect receives at most one offer.  What distinguishes these problems is their sheer size.  With millions of prospects, brute force linear solvers are unsuitable. ...